tests: Do not treat the iotests as separate meson test target anymore

tests: Do not treat the iotests as separate meson test target anymore

If there is a failing iotest, the output is currently not logged to
the console anymore. To get this working again, we need to run the
meson test runner with "--print-errorlogs" (and without "--verbose"
due to a current meson bug that will be fixed here:
https://github.com/mesonbuild/meson/commit/c3f145ca2b9f5.patch ).
We could update the "meson test" call in tests/Makefile.include,
but actually it's nicer and easier if we simply do not treat the
iotests as separate test target anymore and integrate them along
with the other test suites. This has the disadvantage of not getting
the detailed progress indication there anymore, but since that was
only working right in single-threaded "make -j1" mode anyway, it's
not a huge loss right now.

Signed-off-by: Thomas Huth <thuth@redhat.com>
Message-Id: <20220310075048.2303495-1-thuth@redhat.com>
Tested-by: Hanna Reitz <hreitz@redhat.com>
Signed-off-by: Hanna Reitz <hreitz@redhat.com>